projects / fio.git / blame
| Commit | Line | Data |
|---|---|---|
| 243bfe19 JA |
1 | /* |
| 2 | * Really simple exclusive file locking based on filename. | |
| 3 | * No hash indexing, just a list, so only works well for < 100 files or | |
| 4 | * so. But that's more than what fio needs, so should be fine. | |
| 5 | */ | |
| 6 | #include <inttypes.h> | |
| 7 | #include <string.h> | |
| 8 | #include <assert.h> | |
| 9 | ||
| 10 | #include "flist.h" | |
| 11 | #include "filelock.h" | |
| 12 | #include "smalloc.h" | |
| 13 | #include "mutex.h" | |
| 14 | #include "hash.h" | |
| 15 | #include "log.h" | |
| 16 | ||
| 17 | struct fio_filelock { | |
| 18 | uint32_t hash; | |
| 19 | struct fio_mutex lock; | |
| 20 | struct flist_head list; | |
| 21 | unsigned int references; | |
| 22 | }; | |
| 23 | ||
| 24 | static struct flist_head *filelock_list; | |
| 25 | static struct fio_mutex *filelock_lock; | |
| 26 | ||
| 27 | int fio_filelock_init(void) | |
| 28 | { | |
| 29 | filelock_list = smalloc(sizeof(*filelock_list)); | |
| 30 | if (!filelock_list) | |
| 31 | return 1; | |
| 32 | ||
| 33 | INIT_FLIST_HEAD(filelock_list); | |
| 34 | filelock_lock = fio_mutex_init(FIO_MUTEX_UNLOCKED); | |
| 35 | if (!filelock_lock) { | |
| 36 | sfree(filelock_list); | |
| 37 | return 1; | |
| 38 | } | |
| 39 | ||
| 40 | return 0; | |
| 41 | } | |
| 42 | ||
| 43 | void fio_filelock_exit(void) | |
| 44 | { | |
| 45 | if (!filelock_list) | |
| 46 | return; | |
| 47 | ||
| 48 | assert(flist_empty(filelock_list)); | |
| 49 | sfree(filelock_list); | |
| 50 | filelock_list = NULL; | |
| 51 | fio_mutex_remove(filelock_lock); | |
| 52 | filelock_lock = NULL; | |
| 53 | } | |
| 54 | ||
| 55 | static struct fio_filelock *fio_hash_find(uint32_t hash) | |
| 56 | { | |
| 57 | struct flist_head *entry; | |
| 58 | struct fio_filelock *ff; | |
| 59 | ||
| 60 | flist_for_each(entry, filelock_list) { | |
| 61 | ff = flist_entry(entry, struct fio_filelock, list); | |
| 62 | if (ff->hash == hash) | |
| 63 | return ff; | |
| 64 | } | |
| 65 | ||
| 66 | return NULL; | |
| 67 | } | |
| 68 | ||
| 69 | static struct fio_filelock *fio_hash_get(uint32_t hash) | |
| 70 | { | |
| 71 | struct fio_filelock *ff; | |
| 72 | ||
| 73 | ff = fio_hash_find(hash); | |
| 74 | if (!ff) { | |
| 75 | ff = smalloc(sizeof(*ff)); | |
| 76 | ff->hash = hash; | |
| 77 | __fio_mutex_init(&ff->lock, FIO_MUTEX_UNLOCKED); | |
| 78 | ff->references = 0; | |
| 79 | flist_add(&ff->list, filelock_list); | |
| 80 | } | |
| 81 | ||
| 82 | return ff; | |
| 83 | } | |
| 84 | ||
| 85 | int fio_trylock_file(const char *fname) | |
| 86 | { | |
| 87 | struct fio_filelock *ff; | |
| 88 | uint32_t hash; | |
| 89 | ||
| 90 | hash = jhash(fname, strlen(fname), 0); | |
| 91 | ||
| 92 | fio_mutex_down(filelock_lock); | |
| 93 | ff = fio_hash_get(hash); | |
| 94 | ff->references++; | |
| 95 | fio_mutex_up(filelock_lock); | |
| 96 | ||
| 97 | if (!fio_mutex_down_trylock(&ff->lock)) | |
| 98 | return 0; | |
| 99 | ||
| 100 | fio_mutex_down(filelock_lock); | |
| 101 | ||
| 102 | /* | |
| 103 | * If we raced and the only reference to the lock is us, we can | |
| 104 | * grab it | |
| 105 | */ | |
| 106 | if (ff->references != 1) { | |
| 107 | ff->references--; | |
| 108 | ff = NULL; | |
| 109 | } | |
| 110 | ||
| 111 | fio_mutex_up(filelock_lock); | |
| 112 | ||
| 113 | if (ff) { | |
| 114 | fio_mutex_down(&ff->lock); | |
| 115 | return 0; | |
| 116 | } | |
| 117 | ||
| 118 | return 1; | |
| 119 | } | |
| 120 | ||
| 121 | void fio_lock_file(const char *fname) | |
| 122 | { | |
| 123 | struct fio_filelock *ff; | |
| 124 | uint32_t hash; | |
| 125 | ||
| 126 | hash = jhash(fname, strlen(fname), 0); | |
| 127 | ||
| 128 | fio_mutex_down(filelock_lock); | |
| 129 | ff = fio_hash_get(hash); | |
| 130 | ff->references++; | |
| 131 | fio_mutex_up(filelock_lock); | |
| 132 | ||
| 133 | fio_mutex_down(&ff->lock); | |
| 134 | } | |
| 135 | ||
| 136 | void fio_unlock_file(const char *fname) | |
| 137 | { | |
| 138 | struct fio_filelock *ff; | |
| 139 | uint32_t hash; | |
| 140 | ||
| 141 | hash = jhash(fname, strlen(fname), 0); | |
| 142 | ||
| 143 | fio_mutex_down(filelock_lock); | |
| 144 | ||
| 145 | ff = fio_hash_find(hash); | |
| 146 | if (ff) { | |
| 147 | ff->references--; | |
| 148 | fio_mutex_up(&ff->lock); | |
| 149 | if (!ff->references) { | |
| 150 | flist_del(&ff->list); | |
| 151 | sfree(ff); | |
| 152 | } | |
| 153 | } else | |
| 154 | log_err("fio: file not found for unlocking\n"); | |
| 155 | ||
| 156 | fio_mutex_up(filelock_lock); | |
| 157 | } |